Prior-art vaporizing burners have combustion chambers which operate based on the principle that the fuel is applied to a wall or is introduced into a porous material and is evaporated from there and burned. The evaporation, reaction and combustion take place in one space, i.e., they are not separated. The combustion air is either fed directly to the combustion chamber or it is fed in distributed in the entire combustion chamber or radially via holes (over the outer jacket) or via a central air pipe, which is provided with holes and has a flame tube at a certain distance from the outlet of the pipe. The common feature of these combustion chambers is that they have a relatively low output density, i.e., a relatively low outgoing output relative to the volume of the combustion chamber.